Countries waging a regional fight against the Nigerian Islamist militant group Boko Haram will take significant steps toward establishing a joint task force when they meet Thursday in Abuja, Benin's president said.

Boko Haram has killed thousands and displaced about 1.5 million people during a six-year insurgency, seeking to establish an Islamic emirate and extending its reach into neighboring Chad and Cameroon.

At start of the year, it controlled territory about the size of Belgium in northeast Nigeria, but a loosely coordinated offensive by Nigeria's army and troops from Chad, Cameroon and Niger has pushed it out of most of those areas.

Nigeria's neighbors have been urging closer coordination and the deployment of a joint task force, headquartered in the Chadian capital N'Djamena. But diplomats say the process has been slowed down by Nigeria's reservations about foreign troops operating on its soil and by its presidential election in March.

"The discussions we have had with him reassure us," Boni told reporters after talks with French President Francois Hollande in Paris. "We are going to put an end to this odious phenomenon ... This summit will be decisive."

The defense chiefs of Nigeria, Niger, Cameroon, Chad and Benin were meeting in Abuja on Tuesday to lay the groundwork for the task force.

Benin has not deployed any troops against Boko Haram yet, but has agreed in principle to join the force.

Boni said this could begin once the U.N. Security Council passes a resolution, which has been in discussion for several months, endorsing the mission.

"These are international rules and, once it is passed, there won't be any more obstacles," he said.